TABLE 4.
Enumeration of indigenous V. vulnificus in oysters
| Sample lot | Result for:
|
|
|---|---|---|
| Gene probea (log CFU g−1 ± SD) | Real-time PCRb (Log CFU g−1 ± SD) (Ct ± SD) | |
| 1 | 1.8 ± 0.67c | 2.0 ± 0.17 (37.0 ± 0.59) |
| 2d | 3.4 ± 0.15 | 2.3 ± 0.15 (35.7 ± 0.66) |
| 3d | <1.0 ± 0c | 2.0 ± 0.12 (36.6 ± 0.45) |
| 4 | 2.3 ± 0.13 | 2.3 ± 0.16 (35.0 ± 0.16) |
| 5 | 3.4 ± 0.21 | 3.1 ± 0.12 (33.0 ± 0.43) |
| 6 | 3.5 ± 0.35 | 3.6 ± 0.06 (30.6 ± 0.29) |
| 7d | 3.1 ± 0.00 | 2.6 ± 0.06 (32.4 ± 0.17) |
| 8d | 3.1 ± 0.06 | 3.6 ± 0.12 (28.9 ± 0.58) |
| 9 | 2.0 ± 0.20 | 2.4 ± 1.02 (33.1 ± 3.90) |
| 10 | 2.7 ± 0.30 | 2.1 ± 1.04 (33.9 ± 3.80) |
V. vulnificus MO6-24/O levels in uninoculated oyster homogenates were determined by DNA probe colony blot hybridization as described in the text.
Real-time PCR determination of V. vulnificus concentrations was based on the means of triplicate samples, and levels were derived from a standard curve by using the mean of triplicate Ct values for serial 10-fold dilutions of DNA extracted from a known concentration of bacteria as described in the text.
For statistical purposes, samples with probe-negative colony blot hybridizations were assigned a value corresponding to the lowest possible number detectable by the assay (1.0 log CFU g−1).
Lot for which there was a significant difference (P < 0.004) between bacterial concentrations from the gene probe and those from real-time PCR.